FedEx Express is a wholly owned subsidiary of FedEx Corp. and will use the new freighters to modernize its fleet.

“These additional 767 orders will help accelerate our fleet modernization program as we replace our aging MD-10 freighter fleet,” James R. Parker, FedEx Express executive vice president for air operations, said in a statement. “These new 767s will provide significantly improved reliability and are substantially more fuel-efficient than the aircraft they will replace.”

“The 767 Freighter is an ideal fit for FedEx Express,” Brad McMullen, vice president of North America Sales for Boeing Commercial Airplanes, said in a statement. “It will provide a more efficient freighter for FedEx Express’s fleet modernization efforts and help align its network with anticipated cargo volumes.”

Through the end of November, Boeing had 66 unfilled orders for its 767 aircraft.